Rodriguez was optioned to Triple-A Pawtucket on Monday, Michael Silverman of the Boston Herald reports.
The move comes as little surprise after Rodriguez surrendered nine earned runs over 2.2 innings in a loss to the Rays on Monday. The left-hander has been wildly inconsistent through six starts this season, compiling a 1-3 record and an 8.59 ERA. He'll hope to fix his mechanics in the minors and return to his 2015 form. A corresponding move has not yet been announced.